Details

Autor(en) / Beteiligte

• Smith, Charles W.
• Mullan, Dermott J.
• Ness, Norman F.

Titel

Further evidence of wave refraction associated with extended rarefaction events in the solar wind

Ist Teil von

• Journal of Geophysical Research - Space Physics, 2004-01, Vol.109 (A1), p.A01111-n/a

Ort / Verlag

American Geophysical Union

Erscheinungsjahr

2004

Quelle

Wiley Online Library

Beschreibungen/Notizen

• We examine the turbulence and low‐frequency wave properties of three extended rarefaction intervals observed by the Advanced Composition Explorer (ACE) spacecraft in 1999 and 2002 while in orbit at L1. The proton densities drop to values lower than 1 cm−3 and in one case reach 0.1 cm−3. During each interval, the amplitudes of magnetic fluctuations fall to unusually low levels. Moreover, the fluctuations that are present are more Alfvénic in nature than in the typical low‐latitude wind. The constant and near average interplanetary magnetic field during these times results in elevated Alfvén speeds. We suggest that the relative isolation of the rarefaction intervals from sources of turbulence‐generating transients allows wave refraction to become a significant dynamic controlling the evolution of the magnetized plasma. We present analyses of the intervals that support the hypothesis that wave refraction explains the reduced fluctuation levels and enhanced Alfvénicity during these times.